We propose studies to determine the physiological and immunopathological action of brown recluse venom in selected insect species. Additionally, studies to determine the biochemical and pharmacological profile of brown recluse venom components will be attempted. Pure venom from electrically stimulated spiders will be used in all studies. In vivo and in vitro procedures whereby specific microgram amounts of venom will be injected will be made in the insect studies. Preparative disc and analytical disc electrophoresis with U-V absorbance monitoring will be used in the venom purification studies. Additionally Km values, kinetic inactivation, molecular weights and substrate specificity of the separated venom fractions will be made. Venom gland histology studies will be conducted utilizing adult female replete and non-replete specimens.